My experience with modding an external community hasn’t been too bad, but it’s a very lightly used community, and there’s also a mod with a local account, which gives a certain level of safety.

I’m not going to speculate as to her precise identity, but if we take everything the episode showed us at face value:

• She knows what a TARDIS is.

• She did not recognize the Doctor’s police box as a TARDIS until he dematerialized it in front of her, and even then did not seem to know who the Doctor was.

Again, if we are to take all this at face value, I think that narrows the list of candidates significantly, and rules out most, if not all, “familiar” characters.

Could she be a former companion of a pre-Hartnell Doctor? I know the Fugitive Doctor’s TARDIS appeared as a police box to Thirteen, but it’s very possible the chameleon circuit was operational in those days.